| 摘要 |
PURPOSE:To convert a signal with high accuracy, high resoluation at a high conversion speed by adding a low resistance circuit to a resistance string circuit so as to increase the rising speed of the voltage from the resistance string circuit to an object value. CONSTITUTION:In case of selecting a common terminal Zmn of a main resistance string circuit 140, while the terminal Zmn and a common terminal Zs of a sub resistance string circuit 150 short-circuited therewith are kept to the same potential, a current corresponding to a reference voltage from a reference voltage source 30 is given to a series of low resistors Rs of the sub resistance string circuit 150 and a MOSFET Ms rapidly for a prescribed short time (t) and flows slowly to a series of high resistors R of the main string circuit 140 for the remaining time while the short-circuit is released. Thus, the mn-th voltage division caused across the selected common terminal Zmn rises rapidly for a prescribed short time (t) and rises slowly and reaches the stable state. Thus, the voltage division required for the succesive approximation with the analog voltage is obtained as an object with stably and high accuracy state.
|
